混合液回流比对改良A2O工艺效果的调控作用

考察了不同混合液回流比(Ri)条件下,改良A2O工艺的效果.COD去除率受Ri的影响较小,Ri=200%、300%和400%时的COD去除率分别为83.3%、79.9%和84.3%.氮的去除率受其影响明显.不同Ri所引起的缺氧池硝态氮负荷以及实际水力停留时间的变化,使得TN和NH3-N的去除率呈现相互制约的关系.此外,硝酸盐作为反硝化除磷过程的电子受体,Ri为200%和300%时,其浓度较高,对应的TP平均去处率可分别高达73.3%和85.3%;而缺氧池硝酸盐浓度相对较低时(Ri=400%),TP平均去处率仅为54.4%.应对不同进水水质情况对系统脱氮除磷效率提出的要求,可选择适当的Ri,协调工艺对TN、NH3-N以及TP的去除能力,同时,满足较高出水标准的要求.

Regulation of mixture liquid reflux ratio for effect of an improved A2O process

Under different mixture reflux ratio (Ri) conditions, the performance of the modified A2O process was investigated. The COD removal rate (83.3%, 79.9% and 84.3% when Ri = 200%, 300% and 200% respectively) was less influenced by Ri. However, the nitrogen removal rate was obviously influenced by it. The variation of the nitrate load and the actual hydraulic retention time for the anoxic pool caused by different Ri jointly made mutual restriction relations of the removal rate of TN and NH3-N. In addition, the nitrate served as the electron acceptor for the denitrifying phosphorus process. Its concentration was higher when Ri = 200% and 300% (the corresponding TP average removal rate was as high as 73.3% and 85.3%, respectively).Moreover, the TP average removal rate was only 54.4% when relatively low nitrate concentration in the anoxic pool (Ri = 400%). To cope with different inflow water quality, appropriate Ri can be chosen to coordinate the removal ability of TN, NH3-N and TP for the process. As a result, the denitrification and phosphorus removal efficiency can meet the request of higher effluent standard.